I have been wondering about this for a while. Is it possible to counter a laser weapon, given the fact that it travels at the speed of light?

My impression is that no. This leads me to the question, if ETs out there know we are close to developing such lasers, wouldn't they be very concerned and possibly even come here to check out how our laser technology progresses?

I am not saying I believe in UFOs, I still don't know but I am somewhat interested in the subject. A lot of people, including scientists, say that ETs would not waste time and ressources to come here, but maybe this would be a reason.

Is it possible to counter a laser weapon, given the fact that it travels at the speed of light?

Regardless of how "fast it travels" its effect depends on available power 1.
That's why it's not the ultimate weapon.
The job of "killing" can be done more efficiently (currently and for the foreseeable future) with kinetic energy weapons.

This leads me to the question, if ETs out there know we are close to developing such lasers, wouldn't they be very concerned and possibly even come here to check out how our laser technology progresses?

Unlikely.

I am not saying I believe in UFOs, I still don't know but I am somewhat interested in the subject. A lot of people, including scientists, say that ETs would not waste time and ressources to come here, but maybe this would be a reason.

Right.
Similar to the way Europeans used to take regular trips to, say, Africa to check if anyone there had developed the rifle?
Oh, wait, they didn't do that.

1 Among other things. Lasers suffer from dispersion: you also need highly reflective mirrors to focus the beam, and, at ranges in the kilomiles, you also need mirrors that would be, to use the correct engineering terminology, f*ckin' HUGE. Which would add to the overall cost, thus making the case for KE weapons again.

I have been wondering about this for a while. Is it possible to counter a laser weapon, given the fact that it travels at the speed of light?

It would not be possible to dodge out of the way, cause you don't know the beam is on the way until it arrives. But a mirrored surface, or armor the same color as the laser would help protect you.

Its the way nature is!
If you dont like it, go somewhere else....
To another universe, where the rules are simpler
Philosophically more pleasing, more psychologically easy
Prof Richard Feynman (1979) .....

Is it possible to counter a laser weapon, given the fact that it travels at the speed of light?

Regardless of how "fast it travels" its effect depends on available power 1.
That's why it's not the ultimate weapon.
The job of "killing" can be done more efficiently (currently and for the foreseeable future) with kinetic energy weapons.

This leads me to the question, if ETs out there know we are close to developing such lasers, wouldn't they be very concerned and possibly even come here to check out how our laser technology progresses?

Unlikely.

I am not saying I believe in UFOs, I still don't know but I am somewhat interested in the subject. A lot of people, including scientists, say that ETs would not waste time and ressources to come here, but maybe this would be a reason.

Right.
Similar to the way Europeans used to take regular trips to, say, Africa to check if anyone there had developed the rifle?
Oh, wait, they didn't do that.

1 Among other things. Lasers suffer from dispersion: you also need highly reflective mirrors to focus the beam, and, at ranges in the kilomiles, you also need mirrors that would be, to use the correct engineering terminology, f*ckin' HUGE. Which would add to the overall cost, thus making the case for KE weapons again.

I am not talking about our current technology of lasers. Who knows what our technology would be like in decades or centuries regarding lasers.

Europeans didn't go to Africa because they felt there was clearly no threat. If they had thought otherwise they could well have done a preemptive invasion.

I also tend to think that if advanced ETs want to live for a very long time, they would have to be rather paranoid about their survival. If they are not like that they probably wouldn't last long ( in which case the probability that we exist at the same time as them would be significantly lower ).

I also tend to think that if advanced ETs want to live for a very long time, they would have to be rather paranoid about their survival. If they are not like that they probably wouldn't last long ( in which case the probability that we exist at the same time as them would be significantly lower ).

If there are advanced sentient races close enough that they could visit here, and are able to monitor our growth, then they are likely so advanced that they would not be concerned about us doing any real damage to them. It would be like a poking a grizzly bear with a twig. This is all pure speculation of course, seeing as how we haven't detected any traces of any life elsewhere, let alone advanced life.

"For every moment of triumph, for every instance of beauty, many souls must be trampled." Hunter S Thompson
"It is easy to kill someone with a slash of a sword. It is hard to be impossible for others to cut down" - Yagyu Munenori

I also tend to think that if advanced ETs want to live for a very long time, they would have to be rather paranoid about their survival. If they are not like that they probably wouldn't last long ( in which case the probability that we exist at the same time as them would be significantly lower ).

If there are advanced sentient races close enough that they could visit here, and are able to monitor our growth, then they are likely so advanced that they would not be concerned about us doing any real damage to them. It would be like a poking a grizzly bear with a twig. This is all pure speculation of course, seeing as how we haven't detected any traces of any life elsewhere, let alone advanced life.

Like I said, against that argument, there is the argument that the laser might be the ultimate weapon. The only way to prevent being destroyed by a laser ( very advanced laser of course, not the ones we have now ) would be, like I said, to move erratically or to reflect the laser. What else could you think of?

No it wouldn't be fruitless, it would be interesting (with people who are interesting to talk to.)

Since all you would end up with would be unsupported speculation then how is it not fruitless?

Your last answer is of course ridiculous and pathetic pff.

If you're going to make basic mistakes like claiming "comparisons and analogies can be speculative" then what do you expect?

Anyone else has something intelligent to say. I certainly hope so.

Depends what you mean by "intelligent"?
Presumably you have your own ideas of what that means.
I would have thought having some experience of the defence industry, military service and a couple of decades as a military tech consultant/ analyst would have put me in that category (at least with regard to this sub-forum), but apparently you just want uninformed opinion speculation.

Moderator Comment: OK, guys. Rein it in.
Duck, stop being so provocative. Being right doesn't entitle you to also be rude.
Nic, think before you post and don't be so damnably "gee, wow, what if?". That doesn't go down well in one of the serious sub-forums.You could learn a lot from the Duck.

I also tend to think that if advanced ETs want to live for a very long time, they would have to be rather paranoid about their survival. If they are not like that they probably wouldn't last long ( in which case the probability that we exist at the same time as them would be significantly lower ).

If there are advanced sentient races close enough that they could visit here, and are able to monitor our growth, then they are likely so advanced that they would not be concerned about us doing any real damage to them. It would be like a poking a grizzly bear with a twig. This is all pure speculation of course, seeing as how we haven't detected any traces of any life elsewhere, let alone advanced life.

Like I said, against that argument, there is the argument that the laser might be the ultimate weapon. The only way to prevent being destroyed by a laser ( very advanced laser of course, not the ones we have now ) would be, like I said, to move erratically or to reflect the laser. What else could you think of?

Even if the laser is the ultimate weapon, it is still restrained by the speed of light. Provided that the "ETs" lived on the nearest habitable exoplanet discovered, then it would take the laser about 11.9 years to reach them. So we would be viewing a version of their planet that is 11.9 years old and they would be viewing one of ours. Firing a laser at a moving target that far away and expecting to have a precise hit would be terribly difficult feat especially considering dispersion and the chance that something could move into the way. IF they were paranoid like you speculate, they would have ample time to observe us building the device that would fire the laser, meaning they would be able to prepare well in advance. This is such a chain of speculation and what if's that its absurd to even think that this scenario would ever occur.

Last edited by Falconer360; September 10th, 2014 at 05:59 PM.
Reason: Spelling and grammar

"For every moment of triumph, for every instance of beauty, many souls must be trampled." Hunter S Thompson
"It is easy to kill someone with a slash of a sword. It is hard to be impossible for others to cut down" - Yagyu Munenori

Nah.
We couldn't get a "precise hit". At all.
Unless we designate the entire planet as the target.
Even on something as close as the Moon current lasers are four miles wide by the time they get there.

My point exactly. That's what makes this whole death laser idea such a non-threat. I was being generous with the speculation when I said terribly difficult.

"For every moment of triumph, for every instance of beauty, many souls must be trampled." Hunter S Thompson
"It is easy to kill someone with a slash of a sword. It is hard to be impossible for others to cut down" - Yagyu Munenori

Things that defeat a lasar: clouds and dust, mirrors, possibly, thin sheets of metal abalative shielding held away from the surface of a space craft. Lasars are also terrible as hand weapons d/t their vulnariblity to dirt.

Even if the laser is the ultimate weapon, it is still restrained by the speed of light. Provided that the "ETs" lived on the nearest habitable exoplanet discovered, then it would take the laser about 11.9 years to reach them. So we would be viewing a version of their planet that is 11.9 years old and they would be viewing one of ours. Firing a laser at a moving target that far away and expecting to have a precise hit would be terribly difficult feat especially considering dispersion and the chance that something could move into the way. IF they were paranoid like you speculate, they would have ample time to observe us building the device that would fire the laser, meaning they would be able to prepare well in advance. This is such a chain of speculation and what if's that its absurd to even think that this scenario would ever occur.

And if the ET's can travel through space faster than light (kind of a requirement if they're going to become concerned and come visit us) - Then they would probably have the ability to perceive and dodge a laser before it can hit them.

Anyway lasers are incredibly powerful weapons, but not because of their outright destructive abilities. It's because if you shoot a laser, even a fairly weak one, directly into the eyes of a human being you may permanently blind them. Permanently maiming an enemy soldier so they're not dead, but also can't fight, is tactically more useful than killing them anyway.

And of course that particular use of lasers is also banned by international treaties. I guess we'll have to wait for terrorists to start using them so that law can be tested.

Some clocks are only right twice a day, but they are still right when they are right.

Lasers have principal disadvantages in comparison to missiles:
1) They cannot hit a target which is hidden behind a massive object.
2) They cannot follow a moving target.
3) When laser rays hit an armored target they will tend to burn a hole through it and lack shattering and penetrating capability of
an armor-piercing weapon. They will not create as much as fragments.

For this reason I have doubts that laser could ever become a universal weapon.
What is concerning to directed-energy weapon in whole, I think that neutral atoms or heavy ions accelerated to relativistic speeds could have better future than lasers.

The main issue with ion weapons is they don't travel through the atmosphere very well without getting dispersed.

Perhaps you could use Ion weapons together with a laser? Use the laser to burn a path through the air, and then send ions through the path way? I don't know if lasers are actually capable of doing that, or not?

There is still one other issue, which is that if the ions have all the same charge then they will tend to repel each other, so the beam won't stay very concentrated. Using neutrons presents the problem that there is no way to accelerate them, because they don't respond to electromagnetism. (However if you could create a beam of neutrons it would be extremely destructive, because the neutrons would damage the materials on an atomic level.)

Some clocks are only right twice a day, but they are still right when they are right.

The main issue with ion weapons is they don't travel through the atmosphere very well without getting dispersed.

I do not see why Particle-beam weapon should suffer from this problem more than usual bullets. Maybe even less. At least it could be regarded as a close to medium
range weapon.

There is still one other issue, which is that if the ions have all the same charge then they will tend to repel each other, so the beam won't stay very concentrated.

Principally, the faster they move the less they suffer from this problem. At relativistic speeds you would be able to obtain pretty dense ion or electron beams.

Using neutrons presents the problem that there is no way to accelerate them, because they don't respond to electromagnetism. (However if you could create a beam of neutrons it would be extremely destructive, because the neutrons would damage the materials on an atomic level.)

You could use neutral atoms. First you accelerate ions and electrons in parallel and at the exit of the device join them back together.Neutral Particle Beam

The main issue with ion weapons is they don't travel through the atmosphere very well without getting dispersed.

I do not see why Particle-beam weapon should suffer from this problem more than usual bullets. Maybe even less. At least it could be regarded as a close to medium
range weapon.

It is for the same reason as why bullets perform badly underwater when compared with a spear gun. Drag is proportional to the square of an object's velocity, so faster moving objects experience exponentially more drag than slow moving objects.

So a bullet traveling underwater for as few as 10 meters gets slowed down the point where it would barely be able to kill a child.

The reason a spear gun does better underwater is not because it is able to travel faster than the bullet. It is because a spear traveling at slow speed is still lethal, whereas a bullet traveling at slow speed is not very lethal.

This same problem appears when we compare a bullet with an ion gun. The ions from the ion gun will quickly slow down to the same speed as a bullet after they've traveled only a short distance. But an ion traveling at such a slow speed would not be very lethal.

Using neutrons presents the problem that there is no way to accelerate them, because they don't respond to electromagnetism. (However if you could create a beam of neutrons it would be extremely destructive, because the neutrons would damage the materials on an atomic level.)

You could use neutral atoms. First you accelerate ions and electrons in parallel and at the exit of the device join them back together.Neutral Particle Beam

That does look like an interesting prospect. At least it would be useful in outer space.

Or if you were able to punch a hole through the air first using a laser, so they could travel to their target in a vacuum (and thereby experience no drag.)

Some clocks are only right twice a day, but they are still right when they are right.

This same problem appears when we compare a bullet with an ion gun. The ions from the ion gun will quickly slow down to the same speed as a bullet after they've traveled only a short distance. But an ion traveling at such a slow speed would not be very lethal.

Could you provide an exact calculation how fast they will slow down? I do not know, but idea of Gauss cannon is still alive, they conduct many experiments with it and hope to accelerate projectiles to cosmic speeds.Coilgun - Wikipedia, the free encyclopedia